Change-speed transmission



Apr W, ESSE R E. GILL CHANGESPEED TRANSMISSION Filed oct. A2s, 1948 2 Sheets-Sheet l IN V EN TOR. P4 wo/v 56M '2 Sheets-Shes?l 2 Patented Apr. 1Q, 1951 CHANGE SPEED TRANSMIS SION Raymond E. Gill. Indianapolis, Ind., assigner to J. D. Adams Manufacturing Co., Indianapolis, Ind., a corporation of Indiana Application October 28, 194.8, Serial No. 57,106 v 4 Claims. i.

ri'his invention relates to automotive vehicles and more 'particularly to an auxiliary power transmission mechanism which can be used in association with the regular change-speed transmission mechanism incorporated in the vehicle to augment the range of drive-ratios available. One form ci vehicle in connection with which my invention is adapted for use is the machine shown in my co-pending application Serial No. 57,105, led October 28, 1948. The machine to which that application is directed is a more or less conventional form of automotive roadgi'ader converted for use as a rotary snow plow. In the operation of such a machine, it sometimes happens that the snow to be removed is so deep` that the rotary snow. plow cannot dispose or it at a rate great enough to permit operation of the vehicle at even 'the lowest speed attainable with the regular change-speed drive mechanism. It is therefore desirable to equip the regular change-speed transmission mechanism with an auxiliary transmission mechanism capable of providing lower vehicle speeds.

It is the object oi my invention to produce for incorporation in an automotive vehiclean auxiliary transmission mechanism which can be readily applied to a conventional form of changespeed power transmissionmechanism to extend the range of drive ratios attainable. A further object of the invention is to provide an auxiliary transmission mechanism which can be simply and economically manufactured and which can be installed with a minimum of alteration.

One common form of change-speed transmission mechanism` used in vehicles of the type to Which my invention is adapted embodies a primary or driving shaft driven through a pinion rigidly mounted on one end of it, such pinion being located outwardly beyond the shaft bear'- ing and in alignment with an opening in the adjacent wall of the transmission housing. My invention contemplates the removal of the conventional closure for the opening just referred to, the removal of the p-inion, and the application of an auxiliary transmission including a sleeve rigidly connected to the transmission shaft, a. pinion rotatable on said sleeve and of the same diameter as the conventional pinion which is replaced, and gearing for interconnecting the sleeve and its associated pinion at any of a plurality of different speed ratios. The auxiliary transmission is enclosed in a housing which is secured to the main transmission housing over the opening previously referred to.

The accompanying drawings illustrateV my invention:

Fig. 1 is a fragmental side elevation illustrating my auxiliary transmission appliedtothe main transmission of an automotive vehicle, most of such main transmission mechanism being indicated in chain lines; Fig. 2 is a diagrammatic plan View illustrating a portion of the conventional drive mechanism of the automotive vehicle; Fig. 3 is a horizontal section on the line 3--3 of' Fig. 4 illustrating the details of the auxiliary transmission; Fig. 4 is a vertical section on the line -l of Fig. 3; and Fig. 5 is a fragments-l section similar to Fig. 1 illustrating the conventional form of transmission mechanism as unmodified by incorporation of my invention.

In Fig. 1, I have shown a more or less conventional form or" change-speed transmission mechanism le of the sliding-gear type, such transmission mechanism including a drive shaft Il and a driven shaft l2. The driven shaft l2 is shown as operatively connected to a ring gear I3 which is in turn connected with axle shafts l5 of a tandem drive unit. The latter comprises hollow beams I6 pivotally mounted on axle carriers I1 concentric with the shafts l5 and carrying at their ends drive wheels I8 which are connected with the axle shafts l5 through chain drives IS. It will beunderstood, however, that the precise form of vehicle drive illustrated is shown merely by Way of example and forms no part of my invention.

In the vehicle shown in the drawings, it is con-I templated that an engine 2l will be located above the drive unit and operatively connected to the transmission It through a releasable clutch 22, an overdrive gear-set 23, and an idler gear 24, the latter' normallyv meshing with a pinion rigidly secured to one end of the transmission driveshaft ll outwardly beyond a bearing 25 through which said shaft is supported in a transmission housing 25. The normal arrangement is illustrated in Fig. 5, which shows a pinion 2Ts'plined to the end of the drive shaft l l and held thereon by a nut 2t in position to engage the gear 24.

' To permit access to the pinion 21 and the nut ZS,

for purposes of inspection, replacement, or repair, the transmission housing 2% is provided with an opening normally covered by a closure 30 held in place as by screws 3l. Application of my auxiliary'transmission to the parts shown in Fig. 5 involves removal of the cover 3u, the nut 28, and the pinion 2l, and their replacement by the parts now to he described.

My auxiliary transmission is supported in alignment with the shaft Il of the main transmission, conveniently being located in such position by engagement with the Wall of the opening 29 in the transmission housing. If that opening is not accurately concentric with the shaft ll, it may be made so by securing to the end of such shaft an appropriate boring bar, and rotating the shaft Ii while the boring bar is operated to machine the surface of the opening 26. The auxiliary transmission is desirably located from the opening 29 by a flanged bushing 35 which is received in such opening and which in turn receives a machined boss 36 on an auxiliarytransmission housing 31. Adjacent such boss, the housing 31 has an outwardly extending annular flange 33 which overlies the flange on the bushing 35; and the bushing flange and the flange 38 are provided with aligned openings for the reception of screws 39 receivable in the same screw-threaded openings as the screws 3l normally employed to hold the closure 30 in place.

An anti-friction bearing 4l mounted within the bushing 35 and a second anti-friction bearing 42 mounted within the housing 31 provide rotatable support ior a hollow sleeve 43 which extends into the transmission housing 26 and which is provided at its end with an annular series of gear teeth 44 adapted to replace the conventional pinion 21 in engagement with the id-er gear 24. Beyond the anti-friction bearing 42, the sleeve 43 is provided with a second annular series of gear teeth 45 meshing with a gear 46 rotatably supported within the housing 31 on a shaft 41. The gear 46 has rigid with it a pinion 48 meshing with a gear 49 which is supported for rotation about an axis coincident with that of the sleeve 43. Conveniently, the gear 49 is mounted on a stationary stub shaft 56 projecting inwardly of the housing 31 from a plate l `which covers an opening 52 in the wall of the housing 31. The opening 52 is of course large enough to permit passage of the gear 49, so that vthe gear-can beV assembled on to the shaft 5 and the gear and cover 5I positioned as a unit.

Rotatably supported between the gear 49 and ,the adjacent end of the sleeve 43 is a clutch member 55. Conveniently, such clutch member has a hub 56 of considerable axial extent which is rotatably received within the sleeve 43. The clutch member 55 also has an external annular series of clutch teeth 58 which mesh with an internal annular series of teeth 59 provided on an outer clutch member 60 concentric with the clutch member 55. The outer clutch member 60 is adapted for axial movement under the control of a shifter fork 6I rigidly mounted on a rock shaft 62 which extends through one wall of the housing 31 and is provided at its outer end with an arm 63 through which it can be rocked to position the clutch member 6E) in a normal position co-planar with the clutch member 55 or displaced in either axial direction from such normal position;

The gear teeth 45 on the sleeve 43 project outwardly beyond the gear 46, and their projecting portions, at least, are adapted to enter the spaces between the teeth 59 on the outer clutch member 60 so that the outer clutch member can be moved into a position such that it overlaps both the clutch member 55 and the teeth 45 and serves to provide a direct driving connection between the clutch member 55 and the sleeve 43. The hub of the gear 49 is provided with a series of external teeth 65 also adapted to enter between the teeth 58 on the outer clutch member 60, so that by moving the outer clutch member in the opposite direction it can be brought into overlapping relation with the teeth 65 and theinner clutch 4 member 55 to connect the gear 49 to the clutch member 55.

The clutch member 55 is adapted for connection to the drive shaft Il of the main transmission. Io this end, the clutch member 55 may be provided with an internal series of clutch teeth adapted to mesh with a complementary series of teeth on one end of a shaft 61 which extends through the sleeve 43 to a point adjacent the end of the shaft i I, Where it is provided with a second annular series of external clutch teeth 69. A coupling sleeve 10, splined at one end to receive the splined end of the shaft member, is provided at the other end with a series of internal teeth meshing with the teeth 69 on the shaft 61. The coupling sleeve 10 is conveniently held in place on the end of the shaft Il by the same nut 28 which is normally employed to hold the pinion in place.

In installing my transmission, the cover plate or closure 30 and the pinion 21 of the regular transmission are removed. In the auxiliary transmission, the cover 5I with the gear 49 mounted thereon is removed as is also the shaft 61, which is withdrawable outwardly from its position within the sleeve 43. The auxiliary transmission, with the bushing in place thereon, is then applied to the transmission housing 25 and the screws 39 are inserted and tightened. The nut 28 is inserted through the opening 52 and sleeve 43 and tightened on the threaded end of the transmission shaft Il to secure the coupling 10 thereto. Following this, the shaft 61 is inserted and engaged with the coupling member 'Fil and inner clutch member 55, and the cover 5| is secured in place on the housing of the auxiliary transmission. The auxiliary transmission is now ready for operation.

With the outer clutch member 60 in the neutral position shown in the drawings, the auxiliary transmission is inoperative to provide for the transmission of power from the idler gear 24 to the shaft Il of the main transmission. If it is not desired to employ the augmented range of drive-ratios provided by the auxiliary transmission, the shaft 52 is rocked to move the clutch member 60 into a position in which it overlaps both the clutch member 55 and the teeth 45 on the end of the sleeve 43. In this condition, the internal teeth on the clutch member 60 provide a direct connection lbetween the teeth on the sleeve 43 and the inner clutch member 55, which is connected through the shaft 61 and coupling member 1i) to the drive shaft Il of the transmission. If it is desired to take advantage of the drive-ratios which the auxiliary transmission provides, the rock shaft 62 is rocked to move the outer clutch member into overlapping relationship with the inner clutch member and the teeth of the gear 49. In this condition, the

teeth 45 on the sleeve 43 drive the gear 46; and

the pinion 48, rigid with such gear, drives the gear 49 to provide a reduced-speed drive ratio.

I claim as my invention:

1. In combination with a change-speed transmission mechanism having a housing provided with an opening in one wall, a shaft rotatably mounted within said housing in alignment with said opening, a gear adapted normally to mesh with a pinion on said shaft, and means for operatively connecting said gear to a source of power; an auxiliary transmission having a casing secured to said housing at said opening, a sleeve rotatably supported within said casing and extending into said housing in alignment with said shaft, said sleeve having an exterior an nular series of gear teeth meshing with said gear, a second shaft rotatable relatively to said sleeve and disposed coaxially therewithin, means removably coupling said second shaft to the rst named shaft, and power-transmission means 1ocated Within said easing for interconnecting said sleeve and second shaft at any of a plurality'of different speed ratios.

2. The invention set forth in claim 1 with the addition that said coupling means comprises a coupling member secured to said rst shaft and provided with a coaxial series of internal clutch teeth, said power transmission means including a clutch member rotatably supported from and coaxial with said sleeve and having a coaxial series of internal clutch teeth, said second shaft being provided at its ends with annular series of external clutch teeth complementary to and meshing with the internal clutch teeth on said coupling member and clutch member.

3. The invention set forth in claim 1- with the addition that the power transmission means in said casing comprises a gear rotatably supported within the casing coaxally with said sleeve and.

second shaft, gearing interconnecting said sleeve and said last named gear, and clutch means for REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,961,809 Wood June 5, 1934 2,034,141 Gustafson Mar. 17, 1936 2,245,078 Padgett June 10, 1941 2,306,902 Rabe Deo. 29, 1942 2,323,404 Kuchar July 6, 1943 FoREiGN PATENTS Number Country Date 522,260 Great Britain June 13. 1940 

